2,3-dichlorobuta-1,3-diene

Endpoint summary

Description of key information

Although an investigation of skin corrosivity and irritation in which rabbits were treated topically with 2,3 dichloro-1,3 butadiene in a 50/50 mixture with methylene chloride did not indicate the substance to be corrosive or an irritant, the study did not provide sufficient information to determine the potential dermal irritation elicited by skin contact. On the basis of limited information on the ocular irritancy of 2,3 dichloro-1,3 butadiene provided in the OECD SIDS Initial Assessment Report, 2,3 dichloro-1,3 butadiene can be regarded as a potential eye irritant. There are no substantive data from guideline compliant studies or other evidence to indicate that DCBD is a potential skin or respiratory irritant. 

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

In a non-standard study of irritation and corrosivity in which six albino rabbits received topical applications (on skin clipped free of hair on their backs) of 2,3 dichloro-1,3 butadiene /methylene chloride (50/50) no reactions indicative of dermal corrosion or irritation were reported. The study did not provide sufficient information to determine the potential dermal irritation elicited by skin contact with 2,3 dichloro-1,3 butadiene.

Two in vivo studies on the potential ocular irritancy of DCBD have been evaluated by the OECD as part of ICCA HPV initiative (SIDS Initial Assessment Report 2006). Khechumov et al., (1972) reported that inflammation and purulent conjunctivitis were observed in rabbits after drops of 2,3 dichloro-1,3 butadiene (unspecified isomer of unknown purity) were placed in their conjunctival sac. The conjunctivitis was reversible within 21-22 days. Marhold (1986) reported that the application of 500 mg 2,3 dichloro-1,3 butadiene (unknown purity) into the eyes of rabbits for 24 hours lead to a mild eye irritation (Marhold, 1986). In a precautionary approach, on the basis of limited information on the ocular irritancy of DCBD provided in the OECD SIDS Initial Assessment Report, 2,3 dichloro-1,3 butadiene can be regarded as a potential eye irritant.

Respiratory irritation, characterised by degeneration of the nasal olfactory epithelium, has been reported in rats following sub-chronic whole body inhalation exposures to 2,3 dichloro-1,3 butadiene at concentrations up to 50 ppm. These effects have not however been confirmed by acute or single administration guideline-compliant studies.

Effects on skin irritation/corrosion: irritating

Effects on eye irritation: irritating

Effects on respiratory irritation: irritating

Justification for classification or non-classification

On the basis of limited information on the ocular irritancy provided in the OECD SIDS Initial Assessment Report, 2,3 dichloro-1,3 butadiene can be regarded as an eye irritant. GHS classification is proposed as: Eye Irrit. 2; H319: Causes serious eye irritation (67/548/EEC self classification: Xi; R36 Irritant; Irritating to eyes)

In limited studies, 2,3 dichloro-1,3 butadiene administered with methylene chloride (50:50) was not found to be dermal corrosive and no indications of skin irritation were observed. Data from unreliable studies suggest, that 2,3 -dichloro-1,3 -butadiene is irritating to the skin of rabbits. Therefore a classification as Xi, R 38, GHS: skin Irrit. 2, H315: causes skin irritation is proposed.

Although indications of respiratory tract irritation have been reported in a sub-chronic, whole body inhalation exposure study in rats, this has not been confirmed by acute or single administration studies conducted according to the relevant guidelines for respiratory irritation. Although no clear evidence for respiratory irritation is obvious, a respiratory tract irritation cannot be excluded and therefore a classification as Xi, R 37, GHS: STOT Single Exp. 3, H335: May cause respiratory irritation is proposed.